Inhibition Mechanism of Lactiplantibacillus plantarum on the Growth and Biogenic Amine Production in Morganella morganii

Abstract

Morganella morganii, a spoilage bacterium in fermented foods, produces harmful biogenic amines (BAs). Although Lactiplantibacillus plantarum is widely used to inhibit spoilage bacteria, the inhibition pattern and inhibition mechanism of M. morganii by Lpb. plantarum are not well studied. In this study, we analysed the effects of the addition of Lpb. plantarum cell-free supernatant (CFS) on the growth and BA accumulation of M. morganii and revealed the mechanisms of changes in different BAs by using RNA sequencing transcriptome analysis. The results showed that Lpb. plantarum CFS could significantly inhibit M. morganii BAs in a weak acid environment (pH 6), and the main changes were related to metabolism. Carbohydrate and energy metabolism were significantly down-regulated, indicating that Lpb. plantarum CFS inhibited the growth activity and decreased the BA content of M. morganii. In addition, the change in histamine content is also related to the metabolism of its precursor amino acids, the change in putrescine content may also be related to the decrease in precursor amino acid synthesis and amino acid transporter, and the decrease in cadaverine content may also be related to the decrease in the cadaverine transporter. The results of this study help to inhibit the accumulation of harmful metabolites in fermented foods.

Transcriptome Reveals Regulation of Quorum Sensing of Hafnia alvei H4 on the Coculture System of Hafnia alvei H4 and Pseudomonas fluorescens ATCC13525

“…According to Table 1, ldcc was downregulated in the IP-H group compared to the WP-H group for H. alvei H4, while it was not activated in P. fluorescens ATCC13525 of the IP-P group compared to the WP-P group, which may inhibit the decarboxylation of lysine to produce CAD. The synthesis of PUT involves a relatively complex multi-step process [52], is synthesized via ornithine decarboxylation or agmatine deamination. In the IP-H group, there was a notable decrease in the expression of three genes involved in the PUT synthesis pathway: speA, speB, and speF.…”